That looks like a great match for your 3.5. I'd keep using that. I've used Mobil 1 0W-40 in my Integra that specifies 5W-30 before and the UOA came back excellent. FWIW, that oil is only about 1 cSt thicker than the 10W-30 High Mileage oils I have been using in my Firebird.

By running the 0w40 you're robbing power & MPG, increasing oil pressure, and increasing heat. Until you can objectively prove that the 0w40 is necessary over the manufacturer spec'd 5w30, there is no reason to use it.

By running the 0w40 you're robbing power & MPG, increasing oil pressure, and increasing heat. Until you can objectively prove that the 0w40 is necessary over the manufacturer spec'd 5w30, there is no reason to use it.

He might be losing like 1/4 of a horsepower and 0.000002Mpg though really. While there is the potential for impact there I'm doubting it is even measurable.

Yes, he's likely increasing oil pressure. He may be increasing heat (depending on whether oil temps are thermostatically controlled or not), but there isn't really a reason NOT to use it either, as it is likely a better product (it may not be adding any actual benefit but that's an aside and we aren't equipped to measure that here) than what the car specifies.

The only real way to prove which oil would be better other than bench racing would cost as much as the car itself. It appears that he's squeaking by okay (lol) using the wrong oil. I would define wrong oil as one not specified by the manufacturer. I'd give them the nod when it comes to the choice of oil spec's.

A question. Does this engine have a cam timing device that uses engine oil under pressure?

By running the 0w40 you're robbing power & MPG, increasing oil pressure, and increasing heat. Until you can objectively prove that the 0w40 is necessary over the manufacturer spec'd 5w30, there is no reason to use it.

He might be losing like 1/4 of a horsepower and 0.000002Mpg though really. While there is the potential for impact there I'm doubting it is even measurable.

Yes, he's likely increasing oil pressure. He may be increasing heat (depending on whether oil temps are thermostatically controlled or not), but there isn't really a reason NOT to use it either, as it is likely a better product (it may not be adding any actual benefit but that's an aside and we aren't equipped to measure that here) than what the car specifies.

You couldn't be more wrong Overkill. dparm is exactly right.

First, its not 1/4 hp, it would be more like around 1%-2% fuel economy and power difference using a GF-5 qualified 5w-30 (Sequence VID, remember OverK?) compared to a less friction-modified heavier 0w-40. I've seen this many times in SAE techee papers & GF-5 summaries. I suggest you educate yourself on this, its interesting.

Secondly, friction creates heat, its a physical reality. More hydrodynamic friction, more heat, and the around 1% power/MPG benefit is a direct reflection of the joules lost in the form of heating the oil up to higher levels.

I didn't catch the 40 wt. Nissan is pretty picky about running the reccomended weights in their vehicles. I'd like to see a uoa with the 5w30. Might be even better.

Nissan is not too picky in the owner's manual of my 2005 Nissan Pathfinder with the 4.0 V-6. It states that 5W30, 10W30, and 10W40 are OK, with a preference for 5W30. I have used M1 0W40 for several years with no oil usage in a one year, average 9,000 mile OCI.

First, its not 1/4 hp, it would be more like around 1%-2% fuel economy and power difference using a GF-5 qualified 5w-30 (Sequence VID, remember OverK?) compared to a less friction-modified heavier 0w-40. I've seen this many times in SAE techee papers & GF-5 summaries. I suggest you educate yourself on this, its interesting.

Temps the test is performed at are 35C, 65C and 115C. Since the heavier oil is a LOT heavier at lower temperatures, for the period in which the engine sees these temperatures, there will be a measurable effect on fuel economy. HOWEVER, once the engine is warmed up the difference is likely indiscernible. So unless your driving habits reflect constantly running the oil at warm-up temps, the effect on fuel economy is not going to be what you think it is.

Regarding power output, even using your figures, which are likely optimistic, on a 200HP engine we are talking 2-4HP. You can't feel 2-4HP. If you wanted to test the power difference, one could take the car to the drag strip and run 1/4 mile passes with both oils in the sump. The MPH difference between multiple runs on the same oil compared to runs made on the other oil will tell you if you've lost or gained power.

Quote:

Secondly, friction creates heat, its a physical reality. More hydrodynamic friction, more heat, and the around 1% power/MPG benefit is a direct reflection of the joules lost in the form of heating the oil up to higher levels.

OverK, I think you know dparm is right and just enjoy disagreeing.

Shannow did the calculations on that one quite some time back and the loss of power here was minescule. And yes, friction creates heat, and oils get thinner as they get hot. Do you know what the viscosity difference between M1 0w-40 at 190F is and a 5w-30 at 185F is? about 1cSt. Oil temperature plays a far greater role than most realize.

And yes, I enjoy disagreeing, these conversations are a lot of fun I find it funny that we are fretting over the differences between a high VI 0w-40 and your plain-Jane GF-5 5w-30 PCMO when the difference between the spec oil in dparm's car (TWS 10w-60) and either oil is MASSIVELY greater. It is all about perspective. Just the difference between seasons, driving in January vs April is going to affect actual operating viscosity far more than the number on the bottle with the two oils we are discussing. I observed this first-hand with the M5, which has a thermostatically controlled oil cooler.

Then think about the viscosity of the oil in your transmission and differential during the winter

So while I certainly appreciate the fuel economy testing that is performed, I think we also need to remember that this is an engine dyno test in a controlled environment with no powertrain attached to it and the test is designed to replicate the fuel economy gains during warm-up (hence the oil temperatures used). Context is key here. If you do mostly highway, the benefits, which you stated as being 1-2%, become significantly less than that once out of that protocol. See what I'm getting at? The difference between the two oils is 15cSt at 40C and a solid 20cSt at the testing temperature of 35C. But once we are at temp, the difference is only 2.5cSt. And this is also why VI is relevant to fuel economy testing too. A heavier, low-VI 5w-40 would be even thicker at the lower testing temperatures, even a Euro 0w-30 would cede a solid visc difference in this scenario.

I think we get a little too dramatic about some of this stuff sometimes. There are so many factors and variables, we cannot just rely on one test as our benchmark.

The only real way to prove which oil would be better other than bench racing would cost as much as the car itself. It appears that he's squeaking by okay (lol) using the wrong oil. I would define wrong oil as one not specified by the manufacturer. I'd give them the nod when it comes to the choice of oil spec's.

A question. Does this engine have a cam timing device that uses engine oil under pressure?

i believe it does, you're talking about VTC (Variable Timing Control)?appreciate the education, dparm and overkill, people like you make this forum so invaluable.

i might try pennzoil ultra 5w30 next. i'm using mobil 1 0w40 because i've read the additive package is pretty decent, and it's one of the lighter 40-weights, and tends to shear down to a 30-weight anyway.

So while I certainly appreciate the fuel economy testing that is performed, I think we also need to remember that this is an engine dyno test in a controlled environment with no powertrain attached to it and the test is designed to replicate the fuel economy gains during warm-up (hence the oil temperatures used).

Exactly. None of us is ever going to be able to measure the difference in fuel economy between the two oils with any statistical rigour. It's certainly there, but we won't be able to accurately measure it.

I didn't catch the 40 wt. Nissan is pretty picky about running the reccomended weights in their vehicles. I'd like to see a uoa with the 5w30. Might be even better.

Nissan is not too picky in the owner's manual of my 2005 Nissan Pathfinder with the 4.0 V-6. It states that 5W30, 10W30, and 10W40 are OK, with a preference for 5W30. I have used M1 0W40 for several years with no oil usage in a one year, average 9,000 mile OCI.

I'm in south Jersey and I commute to Delaware everyday. It's 90% highway. It's the best commute I've had in years.

Mobil 1 0w40 is arguably Mobil's best oil. It's designed around racing and high performance engines. For whatever reason, people always seem to forget that you can technically use any viscosity in any engine without causing any problems.